lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "ValueEnumerator.h"
  16 #include "llvm/ADT/Triple.h"
  17 #include "llvm/Bitcode/BitstreamWriter.h"
  18 #include "llvm/Bitcode/LLVMBitCodes.h"
  19 #include "llvm/IR/Constants.h"
  20 #include "llvm/IR/DebugInfoMetadata.h"
  21 #include "llvm/IR/DerivedTypes.h"
  22 #include "llvm/IR/InlineAsm.h"
  23 #include "llvm/IR/Instructions.h"
  24 #include "llvm/IR/Module.h"
  25 #include "llvm/IR/Operator.h"
  26 #include "llvm/IR/UseListOrder.h"
  27 #include "llvm/IR/ValueSymbolTable.h"
  28 #include "llvm/Support/CommandLine.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/MathExtras.h"
  31 #include "llvm/Support/Program.h"
  32 #include "llvm/Support/raw_ostream.h"
  33 #include <cctype>
  34 #include <map>
  35 using namespace llvm;
  36
  37 /// These are manifest constants used by the bitcode writer. They do not need to
  38 /// be kept in sync with the reader, but need to be consistent within this file.
  39 enum {
  40   // VALUE_SYMTAB_BLOCK abbrev id's.
  41   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  42   VST_ENTRY_7_ABBREV,
  43   VST_ENTRY_6_ABBREV,
  44   VST_BBENTRY_6_ABBREV,
  45
  46   // CONSTANTS_BLOCK abbrev id's.
  47   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  48   CONSTANTS_INTEGER_ABBREV,
  49   CONSTANTS_CE_CAST_Abbrev,
  50   CONSTANTS_NULL_Abbrev,
  51
  52   // FUNCTION_BLOCK abbrev id's.
  53   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  54   FUNCTION_INST_BINOP_ABBREV,
  55   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  56   FUNCTION_INST_CAST_ABBREV,
  57   FUNCTION_INST_RET_VOID_ABBREV,
  58   FUNCTION_INST_RET_VAL_ABBREV,
  59   FUNCTION_INST_UNREACHABLE_ABBREV,
  60   FUNCTION_INST_GEP_ABBREV,
  61 };
  62
  63 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  64   switch (Opcode) {
  65   default: llvm_unreachable("Unknown cast instruction!");
  66   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  67   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  68   case Instruction::SExt    : return bitc::CAST_SEXT;
  69   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  70   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  71   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  72   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  73   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  74   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  75   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  76   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  77   case Instruction::BitCast : return bitc::CAST_BITCAST;
  78   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  79   }
  80 }
  81
  82 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  83   switch (Opcode) {
  84   default: llvm_unreachable("Unknown binary instruction!");
  85   case Instruction::Add:
  86   case Instruction::FAdd: return bitc::BINOP_ADD;
  87   case Instruction::Sub:
  88   case Instruction::FSub: return bitc::BINOP_SUB;
  89   case Instruction::Mul:
  90   case Instruction::FMul: return bitc::BINOP_MUL;
  91   case Instruction::UDiv: return bitc::BINOP_UDIV;
  92   case Instruction::FDiv:
  93   case Instruction::SDiv: return bitc::BINOP_SDIV;
  94   case Instruction::URem: return bitc::BINOP_UREM;
  95   case Instruction::FRem:
  96   case Instruction::SRem: return bitc::BINOP_SREM;
  97   case Instruction::Shl:  return bitc::BINOP_SHL;
  98   case Instruction::LShr: return bitc::BINOP_LSHR;
  99   case Instruction::AShr: return bitc::BINOP_ASHR;
 100   case Instruction::And:  return bitc::BINOP_AND;
 101   case Instruction::Or:   return bitc::BINOP_OR;
 102   case Instruction::Xor:  return bitc::BINOP_XOR;
 103   }
 104 }
 105
 106 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 107   switch (Op) {
 108   default: llvm_unreachable("Unknown RMW operation!");
 109   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 110   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 111   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 112   case AtomicRMWInst::And: return bitc::RMW_AND;
 113   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 114   case AtomicRMWInst::Or: return bitc::RMW_OR;
 115   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 116   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 117   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 118   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 119   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 120   }
 121 }
 122
 123 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 124   switch (Ordering) {
 125   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 126   case Unordered: return bitc::ORDERING_UNORDERED;
 127   case Monotonic: return bitc::ORDERING_MONOTONIC;
 128   case Acquire: return bitc::ORDERING_ACQUIRE;
 129   case Release: return bitc::ORDERING_RELEASE;
 130   case AcquireRelease: return bitc::ORDERING_ACQREL;
 131   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 132   }
 133   llvm_unreachable("Invalid ordering");
 134 }
 135
 136 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 137   switch (SynchScope) {
 138   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 139   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 140   }
 141   llvm_unreachable("Invalid synch scope");
 142 }
 143
 144 static void WriteStringRecord(unsigned Code, StringRef Str,
 145                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 146   SmallVector<unsigned, 64> Vals;
 147
 148   // Code: [strchar x N]
 149   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 150     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 151       AbbrevToUse = 0;
 152     Vals.push_back(Str[i]);
 153   }
 154
 155   // Emit the finished record.
 156   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 157 }
 158
 159 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 160   switch (Kind) {
 161   case Attribute::Alignment:
 162     return bitc::ATTR_KIND_ALIGNMENT;
 163   case Attribute::AlwaysInline:
 164     return bitc::ATTR_KIND_ALWAYS_INLINE;
 165   case Attribute::Builtin:
 166     return bitc::ATTR_KIND_BUILTIN;
 167   case Attribute::ByVal:
 168     return bitc::ATTR_KIND_BY_VAL;
 169   case Attribute::Convergent:
 170     return bitc::ATTR_KIND_CONVERGENT;
 171   case Attribute::InAlloca:
 172     return bitc::ATTR_KIND_IN_ALLOCA;
 173   case Attribute::Cold:
 174     return bitc::ATTR_KIND_COLD;
 175   case Attribute::InlineHint:
 176     return bitc::ATTR_KIND_INLINE_HINT;
 177   case Attribute::InReg:
 178     return bitc::ATTR_KIND_IN_REG;
 179   case Attribute::JumpTable:
 180     return bitc::ATTR_KIND_JUMP_TABLE;
 181   case Attribute::MinSize:
 182     return bitc::ATTR_KIND_MIN_SIZE;
 183   case Attribute::Naked:
 184     return bitc::ATTR_KIND_NAKED;
 185   case Attribute::Nest:
 186     return bitc::ATTR_KIND_NEST;
 187   case Attribute::NoAlias:
 188     return bitc::ATTR_KIND_NO_ALIAS;
 189   case Attribute::NoBuiltin:
 190     return bitc::ATTR_KIND_NO_BUILTIN;
 191   case Attribute::NoCapture:
 192     return bitc::ATTR_KIND_NO_CAPTURE;
 193   case Attribute::NoDuplicate:
 194     return bitc::ATTR_KIND_NO_DUPLICATE;
 195   case Attribute::NoImplicitFloat:
 196     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 197   case Attribute::NoInline:
 198     return bitc::ATTR_KIND_NO_INLINE;
 199   case Attribute::NonLazyBind:
 200     return bitc::ATTR_KIND_NON_LAZY_BIND;
 201   case Attribute::NonNull:
 202     return bitc::ATTR_KIND_NON_NULL;
 203   case Attribute::Dereferenceable:
 204     return bitc::ATTR_KIND_DEREFERENCEABLE;
 205   case Attribute::DereferenceableOrNull:
 206     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
 207   case Attribute::NoRedZone:
 208     return bitc::ATTR_KIND_NO_RED_ZONE;
 209   case Attribute::NoReturn:
 210     return bitc::ATTR_KIND_NO_RETURN;
 211   case Attribute::NoUnwind:
 212     return bitc::ATTR_KIND_NO_UNWIND;
 213   case Attribute::OptimizeForSize:
 214     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 215   case Attribute::OptimizeNone:
 216     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 217   case Attribute::ReadNone:
 218     return bitc::ATTR_KIND_READ_NONE;
 219   case Attribute::ReadOnly:
 220     return bitc::ATTR_KIND_READ_ONLY;
 221   case Attribute::Returned:
 222     return bitc::ATTR_KIND_RETURNED;
 223   case Attribute::ReturnsTwice:
 224     return bitc::ATTR_KIND_RETURNS_TWICE;
 225   case Attribute::SExt:
 226     return bitc::ATTR_KIND_S_EXT;
 227   case Attribute::StackAlignment:
 228     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 229   case Attribute::StackProtect:
 230     return bitc::ATTR_KIND_STACK_PROTECT;
 231   case Attribute::StackProtectReq:
 232     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 233   case Attribute::StackProtectStrong:
 234     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 235   case Attribute::SafeStack:
 236     return bitc::ATTR_KIND_SAFESTACK;
 237   case Attribute::StructRet:
 238     return bitc::ATTR_KIND_STRUCT_RET;
 239   case Attribute::SanitizeAddress:
 240     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 241   case Attribute::SanitizeThread:
 242     return bitc::ATTR_KIND_SANITIZE_THREAD;
 243   case Attribute::SanitizeMemory:
 244     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 245   case Attribute::UWTable:
 246     return bitc::ATTR_KIND_UW_TABLE;
 247   case Attribute::ZExt:
 248     return bitc::ATTR_KIND_Z_EXT;
 249   case Attribute::EndAttrKinds:
 250     llvm_unreachable("Can not encode end-attribute kinds marker.");
 251   case Attribute::None:
 252     llvm_unreachable("Can not encode none-attribute.");
 253   }
 254
 255   llvm_unreachable("Trying to encode unknown attribute");
 256 }
 257
 258 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 259                                      BitstreamWriter &Stream) {
 260   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 261   if (AttrGrps.empty()) return;
 262
 263   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 264
 265   SmallVector<uint64_t, 64> Record;
 266   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 267     AttributeSet AS = AttrGrps[i];
 268     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 269       AttributeSet A = AS.getSlotAttributes(i);
 270
 271       Record.push_back(VE.getAttributeGroupID(A));
 272       Record.push_back(AS.getSlotIndex(i));
 273
 274       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 275            I != E; ++I) {
 276         Attribute Attr = *I;
 277         if (Attr.isEnumAttribute()) {
 278           Record.push_back(0);
 279           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 280         } else if (Attr.isIntAttribute()) {
 281           Record.push_back(1);
 282           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 283           Record.push_back(Attr.getValueAsInt());
 284         } else {
 285           StringRef Kind = Attr.getKindAsString();
 286           StringRef Val = Attr.getValueAsString();
 287
 288           Record.push_back(Val.empty() ? 3 : 4);
 289           Record.append(Kind.begin(), Kind.end());
 290           Record.push_back(0);
 291           if (!Val.empty()) {
 292             Record.append(Val.begin(), Val.end());
 293             Record.push_back(0);
 294           }
 295         }
 296       }
 297
 298       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 299       Record.clear();
 300     }
 301   }
 302
 303   Stream.ExitBlock();
 304 }
 305
 306 static void WriteAttributeTable(const ValueEnumerator &VE,
 307                                 BitstreamWriter &Stream) {
 308   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 309   if (Attrs.empty()) return;
 310
 311   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 312
 313   SmallVector<uint64_t, 64> Record;
 314   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 315     const AttributeSet &A = Attrs[i];
 316     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 317       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 318
 319     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 320     Record.clear();
 321   }
 322
 323   Stream.ExitBlock();
 324 }
 325
 326 /// WriteTypeTable - Write out the type table for a module.
 327 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 328   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 329
 330   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 331   SmallVector<uint64_t, 64> TypeVals;
 332
 333   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
 334
 335   // Abbrev for TYPE_CODE_POINTER.
 336   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 337   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 338   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 339   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 340   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 341
 342   // Abbrev for TYPE_CODE_FUNCTION.
 343   Abbv = new BitCodeAbbrev();
 344   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 345   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 346   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 347   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 348
 349   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 350
 351   // Abbrev for TYPE_CODE_STRUCT_ANON.
 352   Abbv = new BitCodeAbbrev();
 353   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 355   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 356   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 357
 358   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 359
 360   // Abbrev for TYPE_CODE_STRUCT_NAME.
 361   Abbv = new BitCodeAbbrev();
 362   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 365   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 366
 367   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 368   Abbv = new BitCodeAbbrev();
 369   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 370   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 371   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 373
 374   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 375
 376   // Abbrev for TYPE_CODE_ARRAY.
 377   Abbv = new BitCodeAbbrev();
 378   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 379   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 380   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 381
 382   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 383
 384   // Emit an entry count so the reader can reserve space.
 385   TypeVals.push_back(TypeList.size());
 386   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 387   TypeVals.clear();
 388
 389   // Loop over all of the types, emitting each in turn.
 390   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 391     Type *T = TypeList[i];
 392     int AbbrevToUse = 0;
 393     unsigned Code = 0;
 394
 395     switch (T->getTypeID()) {
 396     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 397     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 398     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 399     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 400     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 401     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 402     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 403     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 404     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 405     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 406     case Type::IntegerTyID:
 407       // INTEGER: [width]
 408       Code = bitc::TYPE_CODE_INTEGER;
 409       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 410       break;
 411     case Type::PointerTyID: {
 412       PointerType *PTy = cast<PointerType>(T);
 413       // POINTER: [pointee type, address space]
 414       Code = bitc::TYPE_CODE_POINTER;
 415       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 416       unsigned AddressSpace = PTy->getAddressSpace();
 417       TypeVals.push_back(AddressSpace);
 418       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 419       break;
 420     }
 421     case Type::FunctionTyID: {
 422       FunctionType *FT = cast<FunctionType>(T);
 423       // FUNCTION: [isvararg, retty, paramty x N]
 424       Code = bitc::TYPE_CODE_FUNCTION;
 425       TypeVals.push_back(FT->isVarArg());
 426       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 427       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 428         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 429       AbbrevToUse = FunctionAbbrev;
 430       break;
 431     }
 432     case Type::StructTyID: {
 433       StructType *ST = cast<StructType>(T);
 434       // STRUCT: [ispacked, eltty x N]
 435       TypeVals.push_back(ST->isPacked());
 436       // Output all of the element types.
 437       for (StructType::element_iterator I = ST->element_begin(),
 438            E = ST->element_end(); I != E; ++I)
 439         TypeVals.push_back(VE.getTypeID(*I));
 440
 441       if (ST->isLiteral()) {
 442         Code = bitc::TYPE_CODE_STRUCT_ANON;
 443         AbbrevToUse = StructAnonAbbrev;
 444       } else {
 445         if (ST->isOpaque()) {
 446           Code = bitc::TYPE_CODE_OPAQUE;
 447         } else {
 448           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 449           AbbrevToUse = StructNamedAbbrev;
 450         }
 451
 452         // Emit the name if it is present.
 453         if (!ST->getName().empty())
 454           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 455                             StructNameAbbrev, Stream);
 456       }
 457       break;
 458     }
 459     case Type::ArrayTyID: {
 460       ArrayType *AT = cast<ArrayType>(T);
 461       // ARRAY: [numelts, eltty]
 462       Code = bitc::TYPE_CODE_ARRAY;
 463       TypeVals.push_back(AT->getNumElements());
 464       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 465       AbbrevToUse = ArrayAbbrev;
 466       break;
 467     }
 468     case Type::VectorTyID: {
 469       VectorType *VT = cast<VectorType>(T);
 470       // VECTOR [numelts, eltty]
 471       Code = bitc::TYPE_CODE_VECTOR;
 472       TypeVals.push_back(VT->getNumElements());
 473       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 474       break;
 475     }
 476     }
 477
 478     // Emit the finished record.
 479     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 480     TypeVals.clear();
 481   }
 482
 483   Stream.ExitBlock();
 484 }
 485
 486 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 487   switch (GV.getLinkage()) {
 488   case GlobalValue::ExternalLinkage:
 489     return 0;
 490   case GlobalValue::WeakAnyLinkage:
 491     return 16;
 492   case GlobalValue::AppendingLinkage:
 493     return 2;
 494   case GlobalValue::InternalLinkage:
 495     return 3;
 496   case GlobalValue::LinkOnceAnyLinkage:
 497     return 18;
 498   case GlobalValue::ExternalWeakLinkage:
 499     return 7;
 500   case GlobalValue::CommonLinkage:
 501     return 8;
 502   case GlobalValue::PrivateLinkage:
 503     return 9;
 504   case GlobalValue::WeakODRLinkage:
 505     return 17;
 506   case GlobalValue::LinkOnceODRLinkage:
 507     return 19;
 508   case GlobalValue::AvailableExternallyLinkage:
 509     return 12;
 510   }
 511   llvm_unreachable("Invalid linkage");
 512 }
 513
 514 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 515   switch (GV.getVisibility()) {
 516   case GlobalValue::DefaultVisibility:   return 0;
 517   case GlobalValue::HiddenVisibility:    return 1;
 518   case GlobalValue::ProtectedVisibility: return 2;
 519   }
 520   llvm_unreachable("Invalid visibility");
 521 }
 522
 523 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 524   switch (GV.getDLLStorageClass()) {
 525   case GlobalValue::DefaultStorageClass:   return 0;
 526   case GlobalValue::DLLImportStorageClass: return 1;
 527   case GlobalValue::DLLExportStorageClass: return 2;
 528   }
 529   llvm_unreachable("Invalid DLL storage class");
 530 }
 531
 532 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 533   switch (GV.getThreadLocalMode()) {
 534     case GlobalVariable::NotThreadLocal:         return 0;
 535     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 536     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 537     case GlobalVariable::InitialExecTLSModel:    return 3;
 538     case GlobalVariable::LocalExecTLSModel:      return 4;
 539   }
 540   llvm_unreachable("Invalid TLS model");
 541 }
 542
 543 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 544   switch (C.getSelectionKind()) {
 545   case Comdat::Any:
 546     return bitc::COMDAT_SELECTION_KIND_ANY;
 547   case Comdat::ExactMatch:
 548     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 549   case Comdat::Largest:
 550     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 551   case Comdat::NoDuplicates:
 552     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 553   case Comdat::SameSize:
 554     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 555   }
 556   llvm_unreachable("Invalid selection kind");
 557 }
 558
 559 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 560   SmallVector<uint16_t, 64> Vals;
 561   for (const Comdat *C : VE.getComdats()) {
 562     // COMDAT: [selection_kind, name]
 563     Vals.push_back(getEncodedComdatSelectionKind(*C));
 564     size_t Size = C->getName().size();
 565     assert(isUInt<16>(Size));
 566     Vals.push_back(Size);
 567     for (char Chr : C->getName())
 568       Vals.push_back((unsigned char)Chr);
 569     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 570     Vals.clear();
 571   }
 572 }
 573
 574 // Emit top-level description of module, including target triple, inline asm,
 575 // descriptors for global variables, and function prototype info.
 576 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 577                             BitstreamWriter &Stream) {
 578   // Emit various pieces of data attached to a module.
 579   if (!M->getTargetTriple().empty())
 580     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 581                       0/*TODO*/, Stream);
 582   const std::string &DL = M->getDataLayoutStr();
 583   if (!DL.empty())
 584     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 585   if (!M->getModuleInlineAsm().empty())
 586     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 587                       0/*TODO*/, Stream);
 588
 589   // Emit information about sections and GC, computing how many there are. Also
 590   // compute the maximum alignment value.
 591   std::map<std::string, unsigned> SectionMap;
 592   std::map<std::string, unsigned> GCMap;
 593   unsigned MaxAlignment = 0;
 594   unsigned MaxGlobalType = 0;
 595   for (const GlobalValue &GV : M->globals()) {
 596     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 597     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
 598     if (GV.hasSection()) {
 599       // Give section names unique ID's.
 600       unsigned &Entry = SectionMap[GV.getSection()];
 601       if (!Entry) {
 602         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 603                           0/*TODO*/, Stream);
 604         Entry = SectionMap.size();
 605       }
 606     }
 607   }
 608   for (const Function &F : *M) {
 609     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 610     if (F.hasSection()) {
 611       // Give section names unique ID's.
 612       unsigned &Entry = SectionMap[F.getSection()];
 613       if (!Entry) {
 614         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 615                           0/*TODO*/, Stream);
 616         Entry = SectionMap.size();
 617       }
 618     }
 619     if (F.hasGC()) {
 620       // Same for GC names.
 621       unsigned &Entry = GCMap[F.getGC()];
 622       if (!Entry) {
 623         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 624                           0/*TODO*/, Stream);
 625         Entry = GCMap.size();
 626       }
 627     }
 628   }
 629
 630   // Emit abbrev for globals, now that we know # sections and max alignment.
 631   unsigned SimpleGVarAbbrev = 0;
 632   if (!M->global_empty()) {
 633     // Add an abbrev for common globals with no visibility or thread localness.
 634     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 635     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 636     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 637                               Log2_32_Ceil(MaxGlobalType+1)));
 638     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
 639                                                            //| explicitType << 1
 640                                                            //| constant
 641     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
 642     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
 643     if (MaxAlignment == 0)                                 // Alignment.
 644       Abbv->Add(BitCodeAbbrevOp(0));
 645     else {
 646       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 647       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 648                                Log2_32_Ceil(MaxEncAlignment+1)));
 649     }
 650     if (SectionMap.empty())                                    // Section.
 651       Abbv->Add(BitCodeAbbrevOp(0));
 652     else
 653       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 654                                Log2_32_Ceil(SectionMap.size()+1)));
 655     // Don't bother emitting vis + thread local.
 656     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 657   }
 658
 659   // Emit the global variable information.
 660   SmallVector<unsigned, 64> Vals;
 661   for (const GlobalVariable &GV : M->globals()) {
 662     unsigned AbbrevToUse = 0;
 663
 664     // GLOBALVAR: [type, isconst, initid,
 665     //             linkage, alignment, section, visibility, threadlocal,
 666     //             unnamed_addr, externally_initialized, dllstorageclass,
 667     //             comdat]
 668     Vals.push_back(VE.getTypeID(GV.getValueType()));
 669     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
 670     Vals.push_back(GV.isDeclaration() ? 0 :
 671                    (VE.getValueID(GV.getInitializer()) + 1));
 672     Vals.push_back(getEncodedLinkage(GV));
 673     Vals.push_back(Log2_32(GV.getAlignment())+1);
 674     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 675     if (GV.isThreadLocal() ||
 676         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 677         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 678         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 679         GV.hasComdat()) {
 680       Vals.push_back(getEncodedVisibility(GV));
 681       Vals.push_back(getEncodedThreadLocalMode(GV));
 682       Vals.push_back(GV.hasUnnamedAddr());
 683       Vals.push_back(GV.isExternallyInitialized());
 684       Vals.push_back(getEncodedDLLStorageClass(GV));
 685       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 686     } else {
 687       AbbrevToUse = SimpleGVarAbbrev;
 688     }
 689
 690     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 691     Vals.clear();
 692   }
 693
 694   // Emit the function proto information.
 695   for (const Function &F : *M) {
 696     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 697     //             section, visibility, gc, unnamed_addr, prologuedata,
 698     //             dllstorageclass, comdat, prefixdata, personalityfn]
 699     Vals.push_back(VE.getTypeID(F.getFunctionType()));
 700     Vals.push_back(F.getCallingConv());
 701     Vals.push_back(F.isDeclaration());
 702     Vals.push_back(getEncodedLinkage(F));
 703     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 704     Vals.push_back(Log2_32(F.getAlignment())+1);
 705     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 706     Vals.push_back(getEncodedVisibility(F));
 707     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 708     Vals.push_back(F.hasUnnamedAddr());
 709     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 710                                        : 0);
 711     Vals.push_back(getEncodedDLLStorageClass(F));
 712     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 713     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 714                                      : 0);
 715     Vals.push_back(
 716         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
 717
 718     unsigned AbbrevToUse = 0;
 719     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 720     Vals.clear();
 721   }
 722
 723   // Emit the alias information.
 724   for (const GlobalAlias &A : M->aliases()) {
 725     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 726     Vals.push_back(VE.getTypeID(A.getType()));
 727     Vals.push_back(VE.getValueID(A.getAliasee()));
 728     Vals.push_back(getEncodedLinkage(A));
 729     Vals.push_back(getEncodedVisibility(A));
 730     Vals.push_back(getEncodedDLLStorageClass(A));
 731     Vals.push_back(getEncodedThreadLocalMode(A));
 732     Vals.push_back(A.hasUnnamedAddr());
 733     unsigned AbbrevToUse = 0;
 734     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 735     Vals.clear();
 736   }
 737 }
 738
 739 static uint64_t GetOptimizationFlags(const Value *V) {
 740   uint64_t Flags = 0;
 741
 742   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 743     if (OBO->hasNoSignedWrap())
 744       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 745     if (OBO->hasNoUnsignedWrap())
 746       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 747   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 748     if (PEO->isExact())
 749       Flags |= 1 << bitc::PEO_EXACT;
 750   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 751     if (FPMO->hasUnsafeAlgebra())
 752       Flags |= FastMathFlags::UnsafeAlgebra;
 753     if (FPMO->hasNoNaNs())
 754       Flags |= FastMathFlags::NoNaNs;
 755     if (FPMO->hasNoInfs())
 756       Flags |= FastMathFlags::NoInfs;
 757     if (FPMO->hasNoSignedZeros())
 758       Flags |= FastMathFlags::NoSignedZeros;
 759     if (FPMO->hasAllowReciprocal())
 760       Flags |= FastMathFlags::AllowReciprocal;
 761   }
 762
 763   return Flags;
 764 }
 765
 766 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 767                                  const ValueEnumerator &VE,
 768                                  BitstreamWriter &Stream,
 769                                  SmallVectorImpl<uint64_t> &Record) {
 770   // Mimic an MDNode with a value as one operand.
 771   Value *V = MD->getValue();
 772   Record.push_back(VE.getTypeID(V->getType()));
 773   Record.push_back(VE.getValueID(V));
 774   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 775   Record.clear();
 776 }
 777
 778 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 779                          BitstreamWriter &Stream,
 780                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 781   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 782     Metadata *MD = N->getOperand(i);
 783     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 784            "Unexpected function-local metadata");
 785     Record.push_back(VE.getMetadataOrNullID(MD));
 786   }
 787   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 788                                     : bitc::METADATA_NODE,
 789                     Record, Abbrev);
 790   Record.clear();
 791 }
 792
 793 static void WriteDILocation(const DILocation *N, const ValueEnumerator &VE,
 794                             BitstreamWriter &Stream,
 795                             SmallVectorImpl<uint64_t> &Record,
 796                             unsigned Abbrev) {
 797   Record.push_back(N->isDistinct());
 798   Record.push_back(N->getLine());
 799   Record.push_back(N->getColumn());
 800   Record.push_back(VE.getMetadataID(N->getScope()));
 801   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 802
 803   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 804   Record.clear();
 805 }
 806
 807 static void WriteGenericDINode(const GenericDINode *N,
 808                                const ValueEnumerator &VE,
 809                                BitstreamWriter &Stream,
 810                                SmallVectorImpl<uint64_t> &Record,
 811                                unsigned Abbrev) {
 812   Record.push_back(N->isDistinct());
 813   Record.push_back(N->getTag());
 814   Record.push_back(0); // Per-tag version field; unused for now.
 815
 816   for (auto &I : N->operands())
 817     Record.push_back(VE.getMetadataOrNullID(I));
 818
 819   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 820   Record.clear();
 821 }
 822
 823 static uint64_t rotateSign(int64_t I) {
 824   uint64_t U = I;
 825   return I < 0 ? ~(U << 1) : U << 1;
 826 }
 827
 828 static void WriteDISubrange(const DISubrange *N, const ValueEnumerator &,
 829                             BitstreamWriter &Stream,
 830                             SmallVectorImpl<uint64_t> &Record,
 831                             unsigned Abbrev) {
 832   Record.push_back(N->isDistinct());
 833   Record.push_back(N->getCount());
 834   Record.push_back(rotateSign(N->getLowerBound()));
 835
 836   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 837   Record.clear();
 838 }
 839
 840 static void WriteDIEnumerator(const DIEnumerator *N, const ValueEnumerator &VE,
 841                               BitstreamWriter &Stream,
 842                               SmallVectorImpl<uint64_t> &Record,
 843                               unsigned Abbrev) {
 844   Record.push_back(N->isDistinct());
 845   Record.push_back(rotateSign(N->getValue()));
 846   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 847
 848   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 849   Record.clear();
 850 }
 851
 852 static void WriteDIBasicType(const DIBasicType *N, const ValueEnumerator &VE,
 853                              BitstreamWriter &Stream,
 854                              SmallVectorImpl<uint64_t> &Record,
 855                              unsigned Abbrev) {
 856   Record.push_back(N->isDistinct());
 857   Record.push_back(N->getTag());
 858   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 859   Record.push_back(N->getSizeInBits());
 860   Record.push_back(N->getAlignInBits());
 861   Record.push_back(N->getEncoding());
 862
 863   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 864   Record.clear();
 865 }
 866
 867 static void WriteDIDerivedType(const DIDerivedType *N,
 868                                const ValueEnumerator &VE,
 869                                BitstreamWriter &Stream,
 870                                SmallVectorImpl<uint64_t> &Record,
 871                                unsigned Abbrev) {
 872   Record.push_back(N->isDistinct());
 873   Record.push_back(N->getTag());
 874   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 875   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 876   Record.push_back(N->getLine());
 877   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 878   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 879   Record.push_back(N->getSizeInBits());
 880   Record.push_back(N->getAlignInBits());
 881   Record.push_back(N->getOffsetInBits());
 882   Record.push_back(N->getFlags());
 883   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 884
 885   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 886   Record.clear();
 887 }
 888
 889 static void WriteDICompositeType(const DICompositeType *N,
 890                                  const ValueEnumerator &VE,
 891                                  BitstreamWriter &Stream,
 892                                  SmallVectorImpl<uint64_t> &Record,
 893                                  unsigned Abbrev) {
 894   Record.push_back(N->isDistinct());
 895   Record.push_back(N->getTag());
 896   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 897   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 898   Record.push_back(N->getLine());
 899   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 900   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 901   Record.push_back(N->getSizeInBits());
 902   Record.push_back(N->getAlignInBits());
 903   Record.push_back(N->getOffsetInBits());
 904   Record.push_back(N->getFlags());
 905   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 906   Record.push_back(N->getRuntimeLang());
 907   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 908   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 909   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 910
 911   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 912   Record.clear();
 913 }
 914
 915 static void WriteDISubroutineType(const DISubroutineType *N,
 916                                   const ValueEnumerator &VE,
 917                                   BitstreamWriter &Stream,
 918                                   SmallVectorImpl<uint64_t> &Record,
 919                                   unsigned Abbrev) {
 920   Record.push_back(N->isDistinct());
 921   Record.push_back(N->getFlags());
 922   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 923
 924   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 925   Record.clear();
 926 }
 927
 928 static void WriteDIFile(const DIFile *N, const ValueEnumerator &VE,
 929                         BitstreamWriter &Stream,
 930                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 931   Record.push_back(N->isDistinct());
 932   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 933   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 934
 935   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 936   Record.clear();
 937 }
 938
 939 static void WriteDICompileUnit(const DICompileUnit *N,
 940                                const ValueEnumerator &VE,
 941                                BitstreamWriter &Stream,
 942                                SmallVectorImpl<uint64_t> &Record,
 943                                unsigned Abbrev) {
 944   Record.push_back(N->isDistinct());
 945   Record.push_back(N->getSourceLanguage());
 946   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 947   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 948   Record.push_back(N->isOptimized());
 949   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 950   Record.push_back(N->getRuntimeVersion());
 951   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 952   Record.push_back(N->getEmissionKind());
 953   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
 954   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
 955   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
 956   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
 957   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
 958   Record.push_back(N->getDWOId());
 959
 960   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
 961   Record.clear();
 962 }
 963
 964 static void WriteDISubprogram(const DISubprogram *N, const ValueEnumerator &VE,
 965                               BitstreamWriter &Stream,
 966                               SmallVectorImpl<uint64_t> &Record,
 967                               unsigned Abbrev) {
 968   Record.push_back(N->isDistinct());
 969   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 970   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 971   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
 972   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 973   Record.push_back(N->getLine());
 974   Record.push_back(VE.getMetadataOrNullID(N->getType()));
 975   Record.push_back(N->isLocalToUnit());
 976   Record.push_back(N->isDefinition());
 977   Record.push_back(N->getScopeLine());
 978   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
 979   Record.push_back(N->getVirtuality());
 980   Record.push_back(N->getVirtualIndex());
 981   Record.push_back(N->getFlags());
 982   Record.push_back(N->isOptimized());
 983   Record.push_back(VE.getMetadataOrNullID(N->getRawFunction()));
 984   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 985   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
 986   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
 987
 988   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
 989   Record.clear();
 990 }
 991
 992 static void WriteDILexicalBlock(const DILexicalBlock *N,
 993                                 const ValueEnumerator &VE,
 994                                 BitstreamWriter &Stream,
 995                                 SmallVectorImpl<uint64_t> &Record,
 996                                 unsigned Abbrev) {
 997   Record.push_back(N->isDistinct());
 998   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 999   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1000   Record.push_back(N->getLine());
1001   Record.push_back(N->getColumn());
1002
1003   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1004   Record.clear();
1005 }
1006
1007 static void WriteDILexicalBlockFile(const DILexicalBlockFile *N,
1008                                     const ValueEnumerator &VE,
1009                                     BitstreamWriter &Stream,
1010                                     SmallVectorImpl<uint64_t> &Record,
1011                                     unsigned Abbrev) {
1012   Record.push_back(N->isDistinct());
1013   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1014   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1015   Record.push_back(N->getDiscriminator());
1016
1017   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1018   Record.clear();
1019 }
1020
1021 static void WriteDINamespace(const DINamespace *N, const ValueEnumerator &VE,
1022                              BitstreamWriter &Stream,
1023                              SmallVectorImpl<uint64_t> &Record,
1024                              unsigned Abbrev) {
1025   Record.push_back(N->isDistinct());
1026   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1027   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1028   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1029   Record.push_back(N->getLine());
1030
1031   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1032   Record.clear();
1033 }
1034
1035 static void WriteDITemplateTypeParameter(const DITemplateTypeParameter *N,
1036                                          const ValueEnumerator &VE,
1037                                          BitstreamWriter &Stream,
1038                                          SmallVectorImpl<uint64_t> &Record,
1039                                          unsigned Abbrev) {
1040   Record.push_back(N->isDistinct());
1041   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1042   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1043
1044   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1045   Record.clear();
1046 }
1047
1048 static void WriteDITemplateValueParameter(const DITemplateValueParameter *N,
1049                                           const ValueEnumerator &VE,
1050                                           BitstreamWriter &Stream,
1051                                           SmallVectorImpl<uint64_t> &Record,
1052                                           unsigned Abbrev) {
1053   Record.push_back(N->isDistinct());
1054   Record.push_back(N->getTag());
1055   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1056   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1057   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1058
1059   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1060   Record.clear();
1061 }
1062
1063 static void WriteDIGlobalVariable(const DIGlobalVariable *N,
1064                                   const ValueEnumerator &VE,
1065                                   BitstreamWriter &Stream,
1066                                   SmallVectorImpl<uint64_t> &Record,
1067                                   unsigned Abbrev) {
1068   Record.push_back(N->isDistinct());
1069   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1070   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1071   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1072   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1073   Record.push_back(N->getLine());
1074   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1075   Record.push_back(N->isLocalToUnit());
1076   Record.push_back(N->isDefinition());
1077   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1078   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1079
1080   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1081   Record.clear();
1082 }
1083
1084 static void WriteDILocalVariable(const DILocalVariable *N,
1085                                  const ValueEnumerator &VE,
1086                                  BitstreamWriter &Stream,
1087                                  SmallVectorImpl<uint64_t> &Record,
1088                                  unsigned Abbrev) {
1089   Record.push_back(N->isDistinct());
1090   Record.push_back(N->getTag());
1091   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1092   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1093   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1094   Record.push_back(N->getLine());
1095   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1096   Record.push_back(N->getArg());
1097   Record.push_back(N->getFlags());
1098
1099   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1100   Record.clear();
1101 }
1102
1103 static void WriteDIExpression(const DIExpression *N, const ValueEnumerator &,
1104                               BitstreamWriter &Stream,
1105                               SmallVectorImpl<uint64_t> &Record,
1106                               unsigned Abbrev) {
1107   Record.reserve(N->getElements().size() + 1);
1108
1109   Record.push_back(N->isDistinct());
1110   Record.append(N->elements_begin(), N->elements_end());
1111
1112   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1113   Record.clear();
1114 }
1115
1116 static void WriteDIObjCProperty(const DIObjCProperty *N,
1117                                 const ValueEnumerator &VE,
1118                                 BitstreamWriter &Stream,
1119                                 SmallVectorImpl<uint64_t> &Record,
1120                                 unsigned Abbrev) {
1121   Record.push_back(N->isDistinct());
1122   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1123   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1124   Record.push_back(N->getLine());
1125   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1126   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1127   Record.push_back(N->getAttributes());
1128   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1129
1130   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1131   Record.clear();
1132 }
1133
1134 static void WriteDIImportedEntity(const DIImportedEntity *N,
1135                                   const ValueEnumerator &VE,
1136                                   BitstreamWriter &Stream,
1137                                   SmallVectorImpl<uint64_t> &Record,
1138                                   unsigned Abbrev) {
1139   Record.push_back(N->isDistinct());
1140   Record.push_back(N->getTag());
1141   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1142   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1143   Record.push_back(N->getLine());
1144   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1145
1146   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1147   Record.clear();
1148 }
1149
1150 static void WriteModuleMetadata(const Module *M,
1151                                 const ValueEnumerator &VE,
1152                                 BitstreamWriter &Stream) {
1153   const auto &MDs = VE.getMDs();
1154   if (MDs.empty() && M->named_metadata_empty())
1155     return;
1156
1157   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1158
1159   unsigned MDSAbbrev = 0;
1160   if (VE.hasMDString()) {
1161     // Abbrev for METADATA_STRING.
1162     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1163     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1164     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1165     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1166     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1167   }
1168
1169   // Initialize MDNode abbreviations.
1170 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1171 #include "llvm/IR/Metadata.def"
1172
1173   if (VE.hasDILocation()) {
1174     // Abbrev for METADATA_LOCATION.
1175     //
1176     // Assume the column is usually under 128, and always output the inlined-at
1177     // location (it's never more expensive than building an array size 1).
1178     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1179     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1180     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1181     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1182     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1183     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1184     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1185     DILocationAbbrev = Stream.EmitAbbrev(Abbv);
1186   }
1187
1188   if (VE.hasGenericDINode()) {
1189     // Abbrev for METADATA_GENERIC_DEBUG.
1190     //
1191     // Assume the column is usually under 128, and always output the inlined-at
1192     // location (it's never more expensive than building an array size 1).
1193     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1194     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1195     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1196     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1197     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1198     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1199     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1200     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1201     GenericDINodeAbbrev = Stream.EmitAbbrev(Abbv);
1202   }
1203
1204   unsigned NameAbbrev = 0;
1205   if (!M->named_metadata_empty()) {
1206     // Abbrev for METADATA_NAME.
1207     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1208     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1209     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1211     NameAbbrev = Stream.EmitAbbrev(Abbv);
1212   }
1213
1214   SmallVector<uint64_t, 64> Record;
1215   for (const Metadata *MD : MDs) {
1216     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1217       assert(N->isResolved() && "Expected forward references to be resolved");
1218
1219       switch (N->getMetadataID()) {
1220       default:
1221         llvm_unreachable("Invalid MDNode subclass");
1222 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1223   case Metadata::CLASS##Kind:                                                  \
1224     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1225     continue;
1226 #include "llvm/IR/Metadata.def"
1227       }
1228     }
1229     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1230       WriteValueAsMetadata(MDC, VE, Stream, Record);
1231       continue;
1232     }
1233     const MDString *MDS = cast<MDString>(MD);
1234     // Code: [strchar x N]
1235     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1236
1237     // Emit the finished record.
1238     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1239     Record.clear();
1240   }
1241
1242   // Write named metadata.
1243   for (const NamedMDNode &NMD : M->named_metadata()) {
1244     // Write name.
1245     StringRef Str = NMD.getName();
1246     Record.append(Str.bytes_begin(), Str.bytes_end());
1247     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1248     Record.clear();
1249
1250     // Write named metadata operands.
1251     for (const MDNode *N : NMD.operands())
1252       Record.push_back(VE.getMetadataID(N));
1253     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1254     Record.clear();
1255   }
1256
1257   Stream.ExitBlock();
1258 }
1259
1260 static void WriteFunctionLocalMetadata(const Function &F,
1261                                        const ValueEnumerator &VE,
1262                                        BitstreamWriter &Stream) {
1263   bool StartedMetadataBlock = false;
1264   SmallVector<uint64_t, 64> Record;
1265   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1266       VE.getFunctionLocalMDs();
1267   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1268     assert(MDs[i] && "Expected valid function-local metadata");
1269     if (!StartedMetadataBlock) {
1270       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1271       StartedMetadataBlock = true;
1272     }
1273     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1274   }
1275
1276   if (StartedMetadataBlock)
1277     Stream.ExitBlock();
1278 }
1279
1280 static void WriteMetadataAttachment(const Function &F,
1281                                     const ValueEnumerator &VE,
1282                                     BitstreamWriter &Stream) {
1283   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1284
1285   SmallVector<uint64_t, 64> Record;
1286
1287   // Write metadata attachments
1288   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1289   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1290   F.getAllMetadata(MDs);
1291   if (!MDs.empty()) {
1292     for (const auto &I : MDs) {
1293       Record.push_back(I.first);
1294       Record.push_back(VE.getMetadataID(I.second));
1295     }
1296     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1297     Record.clear();
1298   }
1299
1300   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1301     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1302          I != E; ++I) {
1303       MDs.clear();
1304       I->getAllMetadataOtherThanDebugLoc(MDs);
1305
1306       // If no metadata, ignore instruction.
1307       if (MDs.empty()) continue;
1308
1309       Record.push_back(VE.getInstructionID(I));
1310
1311       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1312         Record.push_back(MDs[i].first);
1313         Record.push_back(VE.getMetadataID(MDs[i].second));
1314       }
1315       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1316       Record.clear();
1317     }
1318
1319   Stream.ExitBlock();
1320 }
1321
1322 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1323   SmallVector<uint64_t, 64> Record;
1324
1325   // Write metadata kinds
1326   // METADATA_KIND - [n x [id, name]]
1327   SmallVector<StringRef, 8> Names;
1328   M->getMDKindNames(Names);
1329
1330   if (Names.empty()) return;
1331
1332   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1333
1334   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1335     Record.push_back(MDKindID);
1336     StringRef KName = Names[MDKindID];
1337     Record.append(KName.begin(), KName.end());
1338
1339     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1340     Record.clear();
1341   }
1342
1343   Stream.ExitBlock();
1344 }
1345
1346 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1347   if ((int64_t)V >= 0)
1348     Vals.push_back(V << 1);
1349   else
1350     Vals.push_back((-V << 1) | 1);
1351 }
1352
1353 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1354                            const ValueEnumerator &VE,
1355                            BitstreamWriter &Stream, bool isGlobal) {
1356   if (FirstVal == LastVal) return;
1357
1358   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1359
1360   unsigned AggregateAbbrev = 0;
1361   unsigned String8Abbrev = 0;
1362   unsigned CString7Abbrev = 0;
1363   unsigned CString6Abbrev = 0;
1364   // If this is a constant pool for the module, emit module-specific abbrevs.
1365   if (isGlobal) {
1366     // Abbrev for CST_CODE_AGGREGATE.
1367     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1368     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1371     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1372
1373     // Abbrev for CST_CODE_STRING.
1374     Abbv = new BitCodeAbbrev();
1375     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1376     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1377     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1378     String8Abbrev = Stream.EmitAbbrev(Abbv);
1379     // Abbrev for CST_CODE_CSTRING.
1380     Abbv = new BitCodeAbbrev();
1381     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1384     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1385     // Abbrev for CST_CODE_CSTRING.
1386     Abbv = new BitCodeAbbrev();
1387     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1388     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1389     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1390     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1391   }
1392
1393   SmallVector<uint64_t, 64> Record;
1394
1395   const ValueEnumerator::ValueList &Vals = VE.getValues();
1396   Type *LastTy = nullptr;
1397   for (unsigned i = FirstVal; i != LastVal; ++i) {
1398     const Value *V = Vals[i].first;
1399     // If we need to switch types, do so now.
1400     if (V->getType() != LastTy) {
1401       LastTy = V->getType();
1402       Record.push_back(VE.getTypeID(LastTy));
1403       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1404                         CONSTANTS_SETTYPE_ABBREV);
1405       Record.clear();
1406     }
1407
1408     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1409       Record.push_back(unsigned(IA->hasSideEffects()) |
1410                        unsigned(IA->isAlignStack()) << 1 |
1411                        unsigned(IA->getDialect()&1) << 2);
1412
1413       // Add the asm string.
1414       const std::string &AsmStr = IA->getAsmString();
1415       Record.push_back(AsmStr.size());
1416       Record.append(AsmStr.begin(), AsmStr.end());
1417
1418       // Add the constraint string.
1419       const std::string &ConstraintStr = IA->getConstraintString();
1420       Record.push_back(ConstraintStr.size());
1421       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1422       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1423       Record.clear();
1424       continue;
1425     }
1426     const Constant *C = cast<Constant>(V);
1427     unsigned Code = -1U;
1428     unsigned AbbrevToUse = 0;
1429     if (C->isNullValue()) {
1430       Code = bitc::CST_CODE_NULL;
1431     } else if (isa<UndefValue>(C)) {
1432       Code = bitc::CST_CODE_UNDEF;
1433     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1434       if (IV->getBitWidth() <= 64) {
1435         uint64_t V = IV->getSExtValue();
1436         emitSignedInt64(Record, V);
1437         Code = bitc::CST_CODE_INTEGER;
1438         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1439       } else {                             // Wide integers, > 64 bits in size.
1440         // We have an arbitrary precision integer value to write whose
1441         // bit width is > 64. However, in canonical unsigned integer
1442         // format it is likely that the high bits are going to be zero.
1443         // So, we only write the number of active words.
1444         unsigned NWords = IV->getValue().getActiveWords();
1445         const uint64_t *RawWords = IV->getValue().getRawData();
1446         for (unsigned i = 0; i != NWords; ++i) {
1447           emitSignedInt64(Record, RawWords[i]);
1448         }
1449         Code = bitc::CST_CODE_WIDE_INTEGER;
1450       }
1451     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1452       Code = bitc::CST_CODE_FLOAT;
1453       Type *Ty = CFP->getType();
1454       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1455         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1456       } else if (Ty->isX86_FP80Ty()) {
1457         // api needed to prevent premature destruction
1458         // bits are not in the same order as a normal i80 APInt, compensate.
1459         APInt api = CFP->getValueAPF().bitcastToAPInt();
1460         const uint64_t *p = api.getRawData();
1461         Record.push_back((p[1] << 48) | (p[0] >> 16));
1462         Record.push_back(p[0] & 0xffffLL);
1463       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1464         APInt api = CFP->getValueAPF().bitcastToAPInt();
1465         const uint64_t *p = api.getRawData();
1466         Record.push_back(p[0]);
1467         Record.push_back(p[1]);
1468       } else {
1469         assert (0 && "Unknown FP type!");
1470       }
1471     } else if (isa<ConstantDataSequential>(C) &&
1472                cast<ConstantDataSequential>(C)->isString()) {
1473       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1474       // Emit constant strings specially.
1475       unsigned NumElts = Str->getNumElements();
1476       // If this is a null-terminated string, use the denser CSTRING encoding.
1477       if (Str->isCString()) {
1478         Code = bitc::CST_CODE_CSTRING;
1479         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1480       } else {
1481         Code = bitc::CST_CODE_STRING;
1482         AbbrevToUse = String8Abbrev;
1483       }
1484       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1485       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1486       for (unsigned i = 0; i != NumElts; ++i) {
1487         unsigned char V = Str->getElementAsInteger(i);
1488         Record.push_back(V);
1489         isCStr7 &= (V & 128) == 0;
1490         if (isCStrChar6)
1491           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1492       }
1493
1494       if (isCStrChar6)
1495         AbbrevToUse = CString6Abbrev;
1496       else if (isCStr7)
1497         AbbrevToUse = CString7Abbrev;
1498     } else if (const ConstantDataSequential *CDS =
1499                   dyn_cast<ConstantDataSequential>(C)) {
1500       Code = bitc::CST_CODE_DATA;
1501       Type *EltTy = CDS->getType()->getElementType();
1502       if (isa<IntegerType>(EltTy)) {
1503         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1504           Record.push_back(CDS->getElementAsInteger(i));
1505       } else if (EltTy->isFloatTy()) {
1506         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1507           union { float F; uint32_t I; };
1508           F = CDS->getElementAsFloat(i);
1509           Record.push_back(I);
1510         }
1511       } else {
1512         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1513         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1514           union { double F; uint64_t I; };
1515           F = CDS->getElementAsDouble(i);
1516           Record.push_back(I);
1517         }
1518       }
1519     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1520                isa<ConstantVector>(C)) {
1521       Code = bitc::CST_CODE_AGGREGATE;
1522       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1523         Record.push_back(VE.getValueID(C->getOperand(i)));
1524       AbbrevToUse = AggregateAbbrev;
1525     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1526       switch (CE->getOpcode()) {
1527       default:
1528         if (Instruction::isCast(CE->getOpcode())) {
1529           Code = bitc::CST_CODE_CE_CAST;
1530           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1531           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1532           Record.push_back(VE.getValueID(C->getOperand(0)));
1533           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1534         } else {
1535           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1536           Code = bitc::CST_CODE_CE_BINOP;
1537           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1538           Record.push_back(VE.getValueID(C->getOperand(0)));
1539           Record.push_back(VE.getValueID(C->getOperand(1)));
1540           uint64_t Flags = GetOptimizationFlags(CE);
1541           if (Flags != 0)
1542             Record.push_back(Flags);
1543         }
1544         break;
1545       case Instruction::GetElementPtr: {
1546         Code = bitc::CST_CODE_CE_GEP;
1547         const auto *GO = cast<GEPOperator>(C);
1548         if (GO->isInBounds())
1549           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1550         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1551         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1552           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1553           Record.push_back(VE.getValueID(C->getOperand(i)));
1554         }
1555         break;
1556       }
1557       case Instruction::Select:
1558         Code = bitc::CST_CODE_CE_SELECT;
1559         Record.push_back(VE.getValueID(C->getOperand(0)));
1560         Record.push_back(VE.getValueID(C->getOperand(1)));
1561         Record.push_back(VE.getValueID(C->getOperand(2)));
1562         break;
1563       case Instruction::ExtractElement:
1564         Code = bitc::CST_CODE_CE_EXTRACTELT;
1565         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1566         Record.push_back(VE.getValueID(C->getOperand(0)));
1567         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1568         Record.push_back(VE.getValueID(C->getOperand(1)));
1569         break;
1570       case Instruction::InsertElement:
1571         Code = bitc::CST_CODE_CE_INSERTELT;
1572         Record.push_back(VE.getValueID(C->getOperand(0)));
1573         Record.push_back(VE.getValueID(C->getOperand(1)));
1574         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1575         Record.push_back(VE.getValueID(C->getOperand(2)));
1576         break;
1577       case Instruction::ShuffleVector:
1578         // If the return type and argument types are the same, this is a
1579         // standard shufflevector instruction.  If the types are different,
1580         // then the shuffle is widening or truncating the input vectors, and
1581         // the argument type must also be encoded.
1582         if (C->getType() == C->getOperand(0)->getType()) {
1583           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1584         } else {
1585           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1586           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1587         }
1588         Record.push_back(VE.getValueID(C->getOperand(0)));
1589         Record.push_back(VE.getValueID(C->getOperand(1)));
1590         Record.push_back(VE.getValueID(C->getOperand(2)));
1591         break;
1592       case Instruction::ICmp:
1593       case Instruction::FCmp:
1594         Code = bitc::CST_CODE_CE_CMP;
1595         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1596         Record.push_back(VE.getValueID(C->getOperand(0)));
1597         Record.push_back(VE.getValueID(C->getOperand(1)));
1598         Record.push_back(CE->getPredicate());
1599         break;
1600       }
1601     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1602       Code = bitc::CST_CODE_BLOCKADDRESS;
1603       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1604       Record.push_back(VE.getValueID(BA->getFunction()));
1605       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1606     } else {
1607 #ifndef NDEBUG
1608       C->dump();
1609 #endif
1610       llvm_unreachable("Unknown constant!");
1611     }
1612     Stream.EmitRecord(Code, Record, AbbrevToUse);
1613     Record.clear();
1614   }
1615
1616   Stream.ExitBlock();
1617 }
1618
1619 static void WriteModuleConstants(const ValueEnumerator &VE,
1620                                  BitstreamWriter &Stream) {
1621   const ValueEnumerator::ValueList &Vals = VE.getValues();
1622
1623   // Find the first constant to emit, which is the first non-globalvalue value.
1624   // We know globalvalues have been emitted by WriteModuleInfo.
1625   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1626     if (!isa<GlobalValue>(Vals[i].first)) {
1627       WriteConstants(i, Vals.size(), VE, Stream, true);
1628       return;
1629     }
1630   }
1631 }
1632
1633 /// PushValueAndType - The file has to encode both the value and type id for
1634 /// many values, because we need to know what type to create for forward
1635 /// references.  However, most operands are not forward references, so this type
1636 /// field is not needed.
1637 ///
1638 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1639 /// instruction ID, then it is a forward reference, and it also includes the
1640 /// type ID.  The value ID that is written is encoded relative to the InstID.
1641 static bool PushValueAndType(const Value *V, unsigned InstID,
1642                              SmallVectorImpl<unsigned> &Vals,
1643                              ValueEnumerator &VE) {
1644   unsigned ValID = VE.getValueID(V);
1645   // Make encoding relative to the InstID.
1646   Vals.push_back(InstID - ValID);
1647   if (ValID >= InstID) {
1648     Vals.push_back(VE.getTypeID(V->getType()));
1649     return true;
1650   }
1651   return false;
1652 }
1653
1654 /// pushValue - Like PushValueAndType, but where the type of the value is
1655 /// omitted (perhaps it was already encoded in an earlier operand).
1656 static void pushValue(const Value *V, unsigned InstID,
1657                       SmallVectorImpl<unsigned> &Vals,
1658                       ValueEnumerator &VE) {
1659   unsigned ValID = VE.getValueID(V);
1660   Vals.push_back(InstID - ValID);
1661 }
1662
1663 static void pushValueSigned(const Value *V, unsigned InstID,
1664                             SmallVectorImpl<uint64_t> &Vals,
1665                             ValueEnumerator &VE) {
1666   unsigned ValID = VE.getValueID(V);
1667   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1668   emitSignedInt64(Vals, diff);
1669 }
1670
1671 /// WriteInstruction - Emit an instruction to the specified stream.
1672 static void WriteInstruction(const Instruction &I, unsigned InstID,
1673                              ValueEnumerator &VE, BitstreamWriter &Stream,
1674                              SmallVectorImpl<unsigned> &Vals) {
1675   unsigned Code = 0;
1676   unsigned AbbrevToUse = 0;
1677   VE.setInstructionID(&I);
1678   switch (I.getOpcode()) {
1679   default:
1680     if (Instruction::isCast(I.getOpcode())) {
1681       Code = bitc::FUNC_CODE_INST_CAST;
1682       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1683         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1684       Vals.push_back(VE.getTypeID(I.getType()));
1685       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1686     } else {
1687       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1688       Code = bitc::FUNC_CODE_INST_BINOP;
1689       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1690         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1691       pushValue(I.getOperand(1), InstID, Vals, VE);
1692       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1693       uint64_t Flags = GetOptimizationFlags(&I);
1694       if (Flags != 0) {
1695         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1696           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1697         Vals.push_back(Flags);
1698       }
1699     }
1700     break;
1701
1702   case Instruction::GetElementPtr: {
1703     Code = bitc::FUNC_CODE_INST_GEP;
1704     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1705     auto &GEPInst = cast<GetElementPtrInst>(I);
1706     Vals.push_back(GEPInst.isInBounds());
1707     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1708     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1709       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1710     break;
1711   }
1712   case Instruction::ExtractValue: {
1713     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1714     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1715     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1716     Vals.append(EVI->idx_begin(), EVI->idx_end());
1717     break;
1718   }
1719   case Instruction::InsertValue: {
1720     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1721     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1722     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1723     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1724     Vals.append(IVI->idx_begin(), IVI->idx_end());
1725     break;
1726   }
1727   case Instruction::Select:
1728     Code = bitc::FUNC_CODE_INST_VSELECT;
1729     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1730     pushValue(I.getOperand(2), InstID, Vals, VE);
1731     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1732     break;
1733   case Instruction::ExtractElement:
1734     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1735     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1736     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1737     break;
1738   case Instruction::InsertElement:
1739     Code = bitc::FUNC_CODE_INST_INSERTELT;
1740     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1741     pushValue(I.getOperand(1), InstID, Vals, VE);
1742     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1743     break;
1744   case Instruction::ShuffleVector:
1745     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1746     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1747     pushValue(I.getOperand(1), InstID, Vals, VE);
1748     pushValue(I.getOperand(2), InstID, Vals, VE);
1749     break;
1750   case Instruction::ICmp:
1751   case Instruction::FCmp:
1752     // compare returning Int1Ty or vector of Int1Ty
1753     Code = bitc::FUNC_CODE_INST_CMP2;
1754     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1755     pushValue(I.getOperand(1), InstID, Vals, VE);
1756     Vals.push_back(cast<CmpInst>(I).getPredicate());
1757     break;
1758
1759   case Instruction::Ret:
1760     {
1761       Code = bitc::FUNC_CODE_INST_RET;
1762       unsigned NumOperands = I.getNumOperands();
1763       if (NumOperands == 0)
1764         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1765       else if (NumOperands == 1) {
1766         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1767           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1768       } else {
1769         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1770           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1771       }
1772     }
1773     break;
1774   case Instruction::Br:
1775     {
1776       Code = bitc::FUNC_CODE_INST_BR;
1777       const BranchInst &II = cast<BranchInst>(I);
1778       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1779       if (II.isConditional()) {
1780         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1781         pushValue(II.getCondition(), InstID, Vals, VE);
1782       }
1783     }
1784     break;
1785   case Instruction::Switch:
1786     {
1787       Code = bitc::FUNC_CODE_INST_SWITCH;
1788       const SwitchInst &SI = cast<SwitchInst>(I);
1789       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1790       pushValue(SI.getCondition(), InstID, Vals, VE);
1791       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1792       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1793            i != e; ++i) {
1794         Vals.push_back(VE.getValueID(i.getCaseValue()));
1795         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1796       }
1797     }
1798     break;
1799   case Instruction::IndirectBr:
1800     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1801     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1802     // Encode the address operand as relative, but not the basic blocks.
1803     pushValue(I.getOperand(0), InstID, Vals, VE);
1804     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1805       Vals.push_back(VE.getValueID(I.getOperand(i)));
1806     break;
1807
1808   case Instruction::Invoke: {
1809     const InvokeInst *II = cast<InvokeInst>(&I);
1810     const Value *Callee = II->getCalledValue();
1811     FunctionType *FTy = II->getFunctionType();
1812     Code = bitc::FUNC_CODE_INST_INVOKE;
1813
1814     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1815     Vals.push_back(II->getCallingConv() | 1 << 13);
1816     Vals.push_back(VE.getValueID(II->getNormalDest()));
1817     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1818     Vals.push_back(VE.getTypeID(FTy));
1819     PushValueAndType(Callee, InstID, Vals, VE);
1820
1821     // Emit value #'s for the fixed parameters.
1822     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1823       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1824
1825     // Emit type/value pairs for varargs params.
1826     if (FTy->isVarArg()) {
1827       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1828            i != e; ++i)
1829         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1830     }
1831     break;
1832   }
1833   case Instruction::Resume:
1834     Code = bitc::FUNC_CODE_INST_RESUME;
1835     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1836     break;
1837   case Instruction::Unreachable:
1838     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1839     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1840     break;
1841
1842   case Instruction::PHI: {
1843     const PHINode &PN = cast<PHINode>(I);
1844     Code = bitc::FUNC_CODE_INST_PHI;
1845     // With the newer instruction encoding, forward references could give
1846     // negative valued IDs.  This is most common for PHIs, so we use
1847     // signed VBRs.
1848     SmallVector<uint64_t, 128> Vals64;
1849     Vals64.push_back(VE.getTypeID(PN.getType()));
1850     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1851       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1852       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1853     }
1854     // Emit a Vals64 vector and exit.
1855     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1856     Vals64.clear();
1857     return;
1858   }
1859
1860   case Instruction::LandingPad: {
1861     const LandingPadInst &LP = cast<LandingPadInst>(I);
1862     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1863     Vals.push_back(VE.getTypeID(LP.getType()));
1864     Vals.push_back(LP.isCleanup());
1865     Vals.push_back(LP.getNumClauses());
1866     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1867       if (LP.isCatch(I))
1868         Vals.push_back(LandingPadInst::Catch);
1869       else
1870         Vals.push_back(LandingPadInst::Filter);
1871       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1872     }
1873     break;
1874   }
1875
1876   case Instruction::Alloca: {
1877     Code = bitc::FUNC_CODE_INST_ALLOCA;
1878     const AllocaInst &AI = cast<AllocaInst>(I);
1879     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
1880     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1881     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1882     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1883     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1884            "not enough bits for maximum alignment");
1885     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1886     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1887     AlignRecord |= 1 << 6;
1888     Vals.push_back(AlignRecord);
1889     break;
1890   }
1891
1892   case Instruction::Load:
1893     if (cast<LoadInst>(I).isAtomic()) {
1894       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1895       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1896     } else {
1897       Code = bitc::FUNC_CODE_INST_LOAD;
1898       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1899         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1900     }
1901     Vals.push_back(VE.getTypeID(I.getType()));
1902     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1903     Vals.push_back(cast<LoadInst>(I).isVolatile());
1904     if (cast<LoadInst>(I).isAtomic()) {
1905       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1906       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1907     }
1908     break;
1909   case Instruction::Store:
1910     if (cast<StoreInst>(I).isAtomic())
1911       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1912     else
1913       Code = bitc::FUNC_CODE_INST_STORE;
1914     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1915     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
1916     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1917     Vals.push_back(cast<StoreInst>(I).isVolatile());
1918     if (cast<StoreInst>(I).isAtomic()) {
1919       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1920       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1921     }
1922     break;
1923   case Instruction::AtomicCmpXchg:
1924     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1925     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1926     PushValueAndType(I.getOperand(1), InstID, Vals, VE);         // cmp.
1927     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1928     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1929     Vals.push_back(GetEncodedOrdering(
1930                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1931     Vals.push_back(GetEncodedSynchScope(
1932                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1933     Vals.push_back(GetEncodedOrdering(
1934                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1935     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1936     break;
1937   case Instruction::AtomicRMW:
1938     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1939     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1940     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1941     Vals.push_back(GetEncodedRMWOperation(
1942                      cast<AtomicRMWInst>(I).getOperation()));
1943     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1944     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1945     Vals.push_back(GetEncodedSynchScope(
1946                      cast<AtomicRMWInst>(I).getSynchScope()));
1947     break;
1948   case Instruction::Fence:
1949     Code = bitc::FUNC_CODE_INST_FENCE;
1950     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1951     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1952     break;
1953   case Instruction::Call: {
1954     const CallInst &CI = cast<CallInst>(I);
1955     FunctionType *FTy = CI.getFunctionType();
1956
1957     Code = bitc::FUNC_CODE_INST_CALL;
1958
1959     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1960     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1961                    unsigned(CI.isMustTailCall()) << 14 | 1 << 15);
1962     Vals.push_back(VE.getTypeID(FTy));
1963     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1964
1965     // Emit value #'s for the fixed parameters.
1966     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1967       // Check for labels (can happen with asm labels).
1968       if (FTy->getParamType(i)->isLabelTy())
1969         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1970       else
1971         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1972     }
1973
1974     // Emit type/value pairs for varargs params.
1975     if (FTy->isVarArg()) {
1976       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1977            i != e; ++i)
1978         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1979     }
1980     break;
1981   }
1982   case Instruction::VAArg:
1983     Code = bitc::FUNC_CODE_INST_VAARG;
1984     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1985     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1986     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1987     break;
1988   }
1989
1990   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1991   Vals.clear();
1992 }
1993
1994 // Emit names for globals/functions etc.
1995 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1996                                   const ValueEnumerator &VE,
1997                                   BitstreamWriter &Stream) {
1998   if (VST.empty()) return;
1999   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2000
2001   // FIXME: Set up the abbrev, we know how many values there are!
2002   // FIXME: We know if the type names can use 7-bit ascii.
2003   SmallVector<unsigned, 64> NameVals;
2004
2005   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
2006        SI != SE; ++SI) {
2007
2008     const ValueName &Name = *SI;
2009
2010     // Figure out the encoding to use for the name.
2011     bool is7Bit = true;
2012     bool isChar6 = true;
2013     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
2014          C != E; ++C) {
2015       if (isChar6)
2016         isChar6 = BitCodeAbbrevOp::isChar6(*C);
2017       if ((unsigned char)*C & 128) {
2018         is7Bit = false;
2019         break;  // don't bother scanning the rest.
2020       }
2021     }
2022
2023     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2024
2025     // VST_ENTRY:   [valueid, namechar x N]
2026     // VST_BBENTRY: [bbid, namechar x N]
2027     unsigned Code;
2028     if (isa<BasicBlock>(SI->getValue())) {
2029       Code = bitc::VST_CODE_BBENTRY;
2030       if (isChar6)
2031         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2032     } else {
2033       Code = bitc::VST_CODE_ENTRY;
2034       if (isChar6)
2035         AbbrevToUse = VST_ENTRY_6_ABBREV;
2036       else if (is7Bit)
2037         AbbrevToUse = VST_ENTRY_7_ABBREV;
2038     }
2039
2040     NameVals.push_back(VE.getValueID(SI->getValue()));
2041     for (const char *P = Name.getKeyData(),
2042          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
2043       NameVals.push_back((unsigned char)*P);
2044
2045     // Emit the finished record.
2046     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2047     NameVals.clear();
2048   }
2049   Stream.ExitBlock();
2050 }
2051
2052 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2053                          BitstreamWriter &Stream) {
2054   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2055   unsigned Code;
2056   if (isa<BasicBlock>(Order.V))
2057     Code = bitc::USELIST_CODE_BB;
2058   else
2059     Code = bitc::USELIST_CODE_DEFAULT;
2060
2061   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2062   Record.push_back(VE.getValueID(Order.V));
2063   Stream.EmitRecord(Code, Record);
2064 }
2065
2066 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2067                               BitstreamWriter &Stream) {
2068   assert(VE.shouldPreserveUseListOrder() &&
2069          "Expected to be preserving use-list order");
2070
2071   auto hasMore = [&]() {
2072     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2073   };
2074   if (!hasMore())
2075     // Nothing to do.
2076     return;
2077
2078   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2079   while (hasMore()) {
2080     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2081     VE.UseListOrders.pop_back();
2082   }
2083   Stream.ExitBlock();
2084 }
2085
2086 /// WriteFunction - Emit a function body to the module stream.
2087 static void WriteFunction(const Function &F, ValueEnumerator &VE,
2088                           BitstreamWriter &Stream) {
2089   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2090   VE.incorporateFunction(F);
2091
2092   SmallVector<unsigned, 64> Vals;
2093
2094   // Emit the number of basic blocks, so the reader can create them ahead of
2095   // time.
2096   Vals.push_back(VE.getBasicBlocks().size());
2097   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2098   Vals.clear();
2099
2100   // If there are function-local constants, emit them now.
2101   unsigned CstStart, CstEnd;
2102   VE.getFunctionConstantRange(CstStart, CstEnd);
2103   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2104
2105   // If there is function-local metadata, emit it now.
2106   WriteFunctionLocalMetadata(F, VE, Stream);
2107
2108   // Keep a running idea of what the instruction ID is.
2109   unsigned InstID = CstEnd;
2110
2111   bool NeedsMetadataAttachment = F.hasMetadata();
2112
2113   DILocation *LastDL = nullptr;
2114
2115   // Finally, emit all the instructions, in order.
2116   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2117     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2118          I != E; ++I) {
2119       WriteInstruction(*I, InstID, VE, Stream, Vals);
2120
2121       if (!I->getType()->isVoidTy())
2122         ++InstID;
2123
2124       // If the instruction has metadata, write a metadata attachment later.
2125       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2126
2127       // If the instruction has a debug location, emit it.
2128       DILocation *DL = I->getDebugLoc();
2129       if (!DL)
2130         continue;
2131
2132       if (DL == LastDL) {
2133         // Just repeat the same debug loc as last time.
2134         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2135         continue;
2136       }
2137
2138       Vals.push_back(DL->getLine());
2139       Vals.push_back(DL->getColumn());
2140       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2141       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2142       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2143       Vals.clear();
2144
2145       LastDL = DL;
2146     }
2147
2148   // Emit names for all the instructions etc.
2149   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2150
2151   if (NeedsMetadataAttachment)
2152     WriteMetadataAttachment(F, VE, Stream);
2153   if (VE.shouldPreserveUseListOrder())
2154     WriteUseListBlock(&F, VE, Stream);
2155   VE.purgeFunction();
2156   Stream.ExitBlock();
2157 }
2158
2159 // Emit blockinfo, which defines the standard abbreviations etc.
2160 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2161   // We only want to emit block info records for blocks that have multiple
2162   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2163   // Other blocks can define their abbrevs inline.
2164   Stream.EnterBlockInfoBlock(2);
2165
2166   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2167     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2169     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2170     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2171     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2172     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2173                                    Abbv) != VST_ENTRY_8_ABBREV)
2174       llvm_unreachable("Unexpected abbrev ordering!");
2175   }
2176
2177   { // 7-bit fixed width VST_ENTRY strings.
2178     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2179     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2180     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2181     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2182     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2183     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2184                                    Abbv) != VST_ENTRY_7_ABBREV)
2185       llvm_unreachable("Unexpected abbrev ordering!");
2186   }
2187   { // 6-bit char6 VST_ENTRY strings.
2188     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2189     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2190     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2191     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2193     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2194                                    Abbv) != VST_ENTRY_6_ABBREV)
2195       llvm_unreachable("Unexpected abbrev ordering!");
2196   }
2197   { // 6-bit char6 VST_BBENTRY strings.
2198     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2199     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2200     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2201     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2202     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2203     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2204                                    Abbv) != VST_BBENTRY_6_ABBREV)
2205       llvm_unreachable("Unexpected abbrev ordering!");
2206   }
2207
2208
2209
2210   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2211     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2212     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2213     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2214                               VE.computeBitsRequiredForTypeIndicies()));
2215     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2216                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2217       llvm_unreachable("Unexpected abbrev ordering!");
2218   }
2219
2220   { // INTEGER abbrev for CONSTANTS_BLOCK.
2221     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2222     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2223     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2224     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2225                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2226       llvm_unreachable("Unexpected abbrev ordering!");
2227   }
2228
2229   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2230     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2231     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2232     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2233     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2234                               VE.computeBitsRequiredForTypeIndicies()));
2235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2236
2237     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2238                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2239       llvm_unreachable("Unexpected abbrev ordering!");
2240   }
2241   { // NULL abbrev for CONSTANTS_BLOCK.
2242     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2243     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2244     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2245                                    Abbv) != CONSTANTS_NULL_Abbrev)
2246       llvm_unreachable("Unexpected abbrev ordering!");
2247   }
2248
2249   // FIXME: This should only use space for first class types!
2250
2251   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2252     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2253     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2254     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2255     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2256                               VE.computeBitsRequiredForTypeIndicies()));
2257     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2259     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2260                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2261       llvm_unreachable("Unexpected abbrev ordering!");
2262   }
2263   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2264     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2265     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2266     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2267     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2269     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2270                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2271       llvm_unreachable("Unexpected abbrev ordering!");
2272   }
2273   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2274     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2275     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2276     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2280     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2281                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2282       llvm_unreachable("Unexpected abbrev ordering!");
2283   }
2284   { // INST_CAST abbrev for FUNCTION_BLOCK.
2285     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2286     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2289                               VE.computeBitsRequiredForTypeIndicies()));
2290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2291     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2292                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2293       llvm_unreachable("Unexpected abbrev ordering!");
2294   }
2295
2296   { // INST_RET abbrev for FUNCTION_BLOCK.
2297     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2298     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2299     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2300                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2301       llvm_unreachable("Unexpected abbrev ordering!");
2302   }
2303   { // INST_RET abbrev for FUNCTION_BLOCK.
2304     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2305     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2306     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2307     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2308                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2309       llvm_unreachable("Unexpected abbrev ordering!");
2310   }
2311   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2312     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2313     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2314     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2315                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2316       llvm_unreachable("Unexpected abbrev ordering!");
2317   }
2318   {
2319     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2320     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2323                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2324     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2325     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2326     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2327         FUNCTION_INST_GEP_ABBREV)
2328       llvm_unreachable("Unexpected abbrev ordering!");
2329   }
2330
2331   Stream.ExitBlock();
2332 }
2333
2334 /// WriteModule - Emit the specified module to the bitstream.
2335 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2336                         bool ShouldPreserveUseListOrder) {
2337   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2338
2339   SmallVector<unsigned, 1> Vals;
2340   unsigned CurVersion = 1;
2341   Vals.push_back(CurVersion);
2342   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2343
2344   // Analyze the module, enumerating globals, functions, etc.
2345   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2346
2347   // Emit blockinfo, which defines the standard abbreviations etc.
2348   WriteBlockInfo(VE, Stream);
2349
2350   // Emit information about attribute groups.
2351   WriteAttributeGroupTable(VE, Stream);
2352
2353   // Emit information about parameter attributes.
2354   WriteAttributeTable(VE, Stream);
2355
2356   // Emit information describing all of the types in the module.
2357   WriteTypeTable(VE, Stream);
2358
2359   writeComdats(VE, Stream);
2360
2361   // Emit top-level description of module, including target triple, inline asm,
2362   // descriptors for global variables, and function prototype info.
2363   WriteModuleInfo(M, VE, Stream);
2364
2365   // Emit constants.
2366   WriteModuleConstants(VE, Stream);
2367
2368   // Emit metadata.
2369   WriteModuleMetadata(M, VE, Stream);
2370
2371   // Emit metadata.
2372   WriteModuleMetadataStore(M, Stream);
2373
2374   // Emit names for globals/functions etc.
2375   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2376
2377   // Emit module-level use-lists.
2378   if (VE.shouldPreserveUseListOrder())
2379     WriteUseListBlock(nullptr, VE, Stream);
2380
2381   // Emit function bodies.
2382   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2383     if (!F->isDeclaration())
2384       WriteFunction(*F, VE, Stream);
2385
2386   Stream.ExitBlock();
2387 }
2388
2389 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2390 /// header and trailer to make it compatible with the system archiver.  To do
2391 /// this we emit the following header, and then emit a trailer that pads the
2392 /// file out to be a multiple of 16 bytes.
2393 ///
2394 /// struct bc_header {
2395 ///   uint32_t Magic;         // 0x0B17C0DE
2396 ///   uint32_t Version;       // Version, currently always 0.
2397 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2398 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2399 ///   uint32_t CPUType;       // CPU specifier.
2400 ///   ... potentially more later ...
2401 /// };
2402 enum {
2403   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2404   DarwinBCHeaderSize = 5*4
2405 };
2406
2407 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2408                                uint32_t &Position) {
2409   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2410   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2411   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2412   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2413   Position += 4;
2414 }
2415
2416 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2417                                          const Triple &TT) {
2418   unsigned CPUType = ~0U;
2419
2420   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2421   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2422   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2423   // specific constants here because they are implicitly part of the Darwin ABI.
2424   enum {
2425     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2426     DARWIN_CPU_TYPE_X86        = 7,
2427     DARWIN_CPU_TYPE_ARM        = 12,
2428     DARWIN_CPU_TYPE_POWERPC    = 18
2429   };
2430
2431   Triple::ArchType Arch = TT.getArch();
2432   if (Arch == Triple::x86_64)
2433     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2434   else if (Arch == Triple::x86)
2435     CPUType = DARWIN_CPU_TYPE_X86;
2436   else if (Arch == Triple::ppc)
2437     CPUType = DARWIN_CPU_TYPE_POWERPC;
2438   else if (Arch == Triple::ppc64)
2439     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2440   else if (Arch == Triple::arm || Arch == Triple::thumb)
2441     CPUType = DARWIN_CPU_TYPE_ARM;
2442
2443   // Traditional Bitcode starts after header.
2444   assert(Buffer.size() >= DarwinBCHeaderSize &&
2445          "Expected header size to be reserved");
2446   unsigned BCOffset = DarwinBCHeaderSize;
2447   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2448
2449   // Write the magic and version.
2450   unsigned Position = 0;
2451   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2452   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2453   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2454   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2455   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2456
2457   // If the file is not a multiple of 16 bytes, insert dummy padding.
2458   while (Buffer.size() & 15)
2459     Buffer.push_back(0);
2460 }
2461
2462 /// WriteBitcodeToFile - Write the specified module to the specified output
2463 /// stream.
2464 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
2465                               bool ShouldPreserveUseListOrder) {
2466   SmallVector<char, 0> Buffer;
2467   Buffer.reserve(256*1024);
2468
2469   // If this is darwin or another generic macho target, reserve space for the
2470   // header.
2471   Triple TT(M->getTargetTriple());
2472   if (TT.isOSDarwin())
2473     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2474
2475   // Emit the module into the buffer.
2476   {
2477     BitstreamWriter Stream(Buffer);
2478
2479     // Emit the file header.
2480     Stream.Emit((unsigned)'B', 8);
2481     Stream.Emit((unsigned)'C', 8);
2482     Stream.Emit(0x0, 4);
2483     Stream.Emit(0xC, 4);
2484     Stream.Emit(0xE, 4);
2485     Stream.Emit(0xD, 4);
2486
2487     // Emit the module.
2488     WriteModule(M, Stream, ShouldPreserveUseListOrder);
2489   }
2490
2491   if (TT.isOSDarwin())
2492     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2493
2494   // Write the generated bitstream to "Out".
2495   Out.write((char*)&Buffer.front(), Buffer.size());
2496 }